Method of securing and transferring a load between a vessel and an offshore installation and an apparatus therefor

ABSTRACT

The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises moving at least a portion of a vessel underneath the hull of the offshore jack-up or within a cut-out of the hull when the hull is positioned out of the water and the legs engage the seafloor. A stabilizing mechanism mounted on the jack-up is engaged against the vessel. The stabilizing mechanism is pushed down on the vessel to increase the buoyant force acting on the vessel.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a Continuation of U.S. application Ser. No.16/738,323, filed Jan. 9, 2020, which is a Continuation of U.S.application Ser. No. 16/434,844, filed Jun. 7, 2019, which claimspriority under 35 U.S.C. § 119 to Danish Patent Application No. PA 201900389, filed Apr. 1, 2019, the entire contents of each of which areincorporated herein by reference.

BACKGROUND Technical Field

The present invention relates to a method of securing and transferring aload between a vessel and an offshore installation and an apparatustherefor. In particular, the present invention relates to transferring aload between a vessel and an offshore jack-up installation.

Description of Related Art

In the offshore industry operations are performed from specialisedplatforms or vessels, known colloquially as “rigs”. Multiple types ofrig exist, such as fixed platforms, jack-ups, semi-submersibles, ships,barges and the like. The particular type of rig used can depend on anumber of factors, such as water depth, rig availability, operationalrequirements and the like.

Offshore jack-up rigs can be used for different purposes. Some offshorejack-up rigs are used to drill and extract oil and gas. However, inorder to reduce the dependence on limited fossil fuel resources aroundthe world, there has been an increasing demand for renewable energygeneration. One such source of renewable energy that has becomeincreasingly reliable is wind energy generation.

Typically, electricity is generated from the wind with wind turbinegenerators (WTG) installed in locations with a reliable prevailing wind.Some wind turbine generators have been installed on land in windy areassuch as on hilltops. Wind turbine generators installed on land are alsoknown as “onshore” wind turbine generators. However, larger wind turbinegenerators can be installed in coastal waters. Wind turbine generatorsinstalled in coastal waters, the sea or deep ocean are also known as“offshore” wind turbine generators.

Accordingly, offshore jack-up rigs can be used for other offshoreinstallations such as offshore WTGs. Offshore wind turbine generatorinstallation is typically carried out in separate stages. One currentmethod of installation is to anchor a foundation to the seabed using amonopile foundation. This is a steel and/or concrete tube which is fixedto and protrudes from the seabed. A transition piece (TP) is fixed tothe monopile foundation and the transition piece projects out of thewater. The offshore wind turbine generator is then fixed to thetransition piece.

One such jack-up rig for installing WTGs is disclosed in EP 2 886 722.This discloses a plurality of WTG components stored on the deck of thejack-up rig ready for installation at a designated offshore area. Aproblem with the jack-up rig is that the WTG components are loaded onthe deck of the jack-up rig in port. When all the WTG components areinstalled, the jack-up rig must sail back to port to be replenished withmore WTG components. This reduces the amount of time that the jack-uprig can be used to install offshore WTGs in the designated offshorearea.

KR20170109094 shows a jack-up vessel with a detachable deck comprisingthe WTG components. Once the jack-up vessel is in the designatedoffshore area, the legs extend and lift up a platform from the vesselusing a rail system. A problem with this is that legs and platformrequire the jack-up vessel to move the legs and platforms betweeninstallation sites. Furthermore, when the vessel sails away from thelegs, the vessel requires very calm weather in order not to collide withthe legs (e.g. due to heave, roll or sway of the vessel due to thewaves.

Alternatively, a jack-up rig can be supplied with WTG components via asupply vessel. One such supply vessel is shown in KR20180003214. Aproblem with the supply vessel is that the transfer of the WTGcomponents to the jack-up vessel can be difficult especially in badweather. This means that the jack-up vessel cannot be resupplied untilthere is a suitably long calm weather window.

SUMMARY

Examples described hereinafter aim to address the aforementionedproblems.

According to an aspect of the present invention there is a method ofsecuring a vessel with an offshore jack-up having a hull and a pluralityof moveable legs engageable with the seafloor and the offshore jack-upis arranged to move the legs with respect to the hull to position thehull out of the water, wherein the method comprises: moving at least aportion of a vessel underneath the hull of the offshore jack-up orwithin a cut-out of the hull when the hull is positioned out of thewater and the legs engage the seafloor; engaging a stabilizing mechanismmounted on the jack-up against the vessel; pushing the stabilizingmechanism down on the vessel to increase the buoyant force acting on thevessel; and lifting a cargo from the vessel with a plurality of liftingarms mounted on the jack-up after the stabilizing mechanism pushes downon the vessel.

Optionally, the stabilizing mechanism can push against the deck of thevessel.

Optionally the stabilizing mechanism may be a plurality of stabilizingarms.

Optionally the vessel can be substantially fixed with respect to thehull when stabilizing mechanism pushes down on the vessel.

Optionally the vessel may be accessible from above when the vessel iswithin the cut-out.

Optionally the offshore jack-up may comprises a crane with a workingarea extending over the cut-out portion of the hull.

Optionally the hull may comprises at least one guide structure forlaterally positioning the vessel underneath the hull or within thecut-out.

Optionally the at least one guide structure may be a first guidestructure and a second guide structure and the plurality of stabilizingarms are mounted along the first guide structure and the second guidestructure.

Optionally the hull may comprises at least one stop structure forlimiting the extent the vessel moves forward underneath the hull.

Optionally the stabilizing mechanism may be extendible underneath thehull.

Optionally each of the stabilizing arms may comprise a self-seating headfor engaging in a reciprocal hole in the deck of the vessel.

Optionally at least one pair of stabilizing arms may engage the vesselon opposites sides of the centre of buoyancy of the vessel.

Optionally the plurality of the stabilizing arms may engage the vesselat substantially the same time.

Optionally the cargo load may be one or more of a wind turbine tower, anacelle, wind turbine blades, a wind turbine generator component,equipment, personnel, supplies, a transition piece, a monopile, a jacketand/or any other components of an offshore wind turbine generator orwind turbine generator farm.

Optionally the method may comprise placing cargo on the deck of thevessel whilst the stabilizing mechanism pushes down on the vessel.

Optionally the method may comprise engaging a bow of the vessel with amoveable coupling mechanism mounted on the hull.

Optionally the vessel may be pivotable about the moveable couplingmechanism before the stabilizing mechanism engages the vessel.

Optionally the vessel may comprise a plurality of hulls.

In another aspect of the invention there is provided an offshore jack-upcomprising: a hull; a plurality of moveable legs engageable with theseafloor, wherein the offshore installation is arranged to move the legswith respect to the hull to position the hull out of the water when thelegs engage the seafloor; a stabilizing mechanism mounted on the jack-upengageable with a vessel positioned underneath the hull of the offshorejack-up or within a cut-out in the hull when the hull is positioned outof the water; wherein when the stabilizing mechanism push down on thevessel, the buoyant force acting on the vessel increases; and aplurality of lifting arms mounted on the jack-up arranged to lift acargo on the vessel after the stabilizing mechanism pushes down on thevessel.

In yet another aspect of the invention there is provided a method ofsecuring a vessel with an offshore installation fixed to the seabedhaving an above-water structure, the method comprising: moving at leasta portion of a vessel underneath the above-water structure of theoffshore installation or within a cut-out of the above-water structure;engaging a stabilizing mechanism mounted on the above-water structure onthe vessel; pushing the stabilizing mechanism down on the vessel toincrease the buoyant force acting against the vessel; and lifting acargo from the vessel with a plurality of lifting arms mounted on theoffshore installation after the stabilizing mechanism pushes down on thevessel.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other aspects and further examples are also described in thefollowing detailed description and in the attached claims with referenceto the accompanying drawings, in which:

FIG. 1 shows a perspective view of an offshore jack-up according to anexample;

FIG. 2 shows a side view of an offshore jack-up with an unsecured vesselaccording to an example;

FIG. 3 shows a side view of an offshore jack-up with a secured vesselaccording to an example;

FIG. 4 shows a plan view of an offshore jack-up according to an example;

FIG. 5 shows an underneath plan view of an offshore jack-up according toan example;

FIG. 6 shows a plan view of an offshore jack-up with a secured vesselaccording to an example;

FIG. 7 shows a front side view of an offshore jack-up with an unsecuredvessel adjacent to the offshore jack-up according to an example;

FIG. 8 shows a front side view of an offshore jack-up with a securedvessel according to an example;

FIG. 9 shows another front side view of an offshore jack-up with asecured vessel according to an example;

FIG. 10 shows a perspective view of a load carrying platform accordingto an example;

FIGS. 11 a, 11 b and 11 c show a schematic side cross sectional view ofpart of a vessel and an offshore jack-up according to an example;

FIGS. 12 and 13 show a flow diagram of methods according to an example;

FIG. 14 shows an underneath plan view of an offshore jack-up accordingto an example; and

FIG. 15 shows a plan view of an offshore jack-up with a secured vesselaccording to an example.

DETAILED DESCRIPTION

Examples of the present disclosure relate to methods and apparatus forsecuring and transferring a load between a vessel and an offshorejack-up. In some examples, any form of offshore installation and anyform of vessel may be utilised. However, for the illustrative purposesonly, the following description is provided with reference to anoffshore jack-up such as a jack-up rig, a jack-up barge, a liftingvessel or a jack-up vessel.

FIG. 1 shows a perspective view of an offshore jack-up 100 according toan example. The offshore jack-up 100 is a jack-up rig 100 and the term“jack-up” 100 will be used hereinafter. However, the methods andapparatus discussed below can be used with other offshore installationsand other forms of jack-up equipment such as jack-up vessels or jack-upbarges.

The jack-up 100 comprises a hull 102 and a plurality of moveable legs104 a, 104 b, 104 c, 104 d. In the example as shown in FIG. 1 , thereare four moveable legs 104 a, 104 b, 104 c, 104 d, but in other examplesthere can be three moveable legs or more than four moveable legs. Insome examples as shown in FIG. 1 , the moveable legs 104 a, 104 b, 104c, 104 d, are open truss legs, but in other examples the moveable legs104 a, 104 b, 104 c, 104 d, are solid cylindrical legs.

The moveable legs 104 a, 104 b, 104 c, 104 d extend downwardly throughthe hull 102 via respective jacking mechanisms 106 a, 106 b, 106 c, 106d. The jacking mechanisms 106 a, 106 b, 106 c, 106 d comprise a casingfor protecting the jacking mechanisms 106 a, 106 b, 106 c, 106 d. Thejacking mechanisms 106 a, 106 b, 106 c, 106 d, in some examples, arehydraulically operated rack and pinion mechanisms. The operation of ajack-up 100 is known and will not be discussed in further detail.

In FIG. 1 the jack-up 100 is illustrated with the moveable 104 a, 104 b,104 c, 104 d 14 in an extended position. When the moveable legs 104 a,104 b, 104 c, 104 d are in the extended position, the moveable legs 104a, 104 b, 104 c, 104 d extend down to and engage the seafloor 200. Forthe purposes of clarity, the seafloor 200 is not shown in FIG. 1 and themoveable legs 104 a, 104 b, 104 c, 104 d are partially shown. Theengagement of the moveable legs 104 a, 104 b, 104 c, 104 d with theseafloor 200 is better shown in e.g. FIGS. 2 and 3 .

The moveable legs 104 a, 104 b, 104 c, 104 d are moveable between theextended position and a retracted position, such that the hull 102 mayfloat on the surface 202 of a body of water 204, and may be transportedto a desired location. In some examples, the jack-up 100 comprises oneor more propulsors 210 such as an azimuthing thruster (as shown in FIG.2 ) for moving the jack-up 100 between WTG installation sites. In anexample, the jack-up 100 comprises four azimuthing thrusters 210 in eachcorner of the hull 102 as shown in FIG. 5 . Alternatively, in someexamples, the jack-up 100 does not comprise propulsors 210 and is towedwhen the jack-up 100 is moved. In some examples, the jack-up 100 istowed with a vessel between the port and the WTG installation sitewhether or not the jack-up 100 comprises propulsors 210.

FIG. 1 shows the jack-up 100 in an operational configuration where thehull 102 has been raised above the surface 202 of the water 204. Duringoperation of the jack-up 100, a crane 108 can lift loads for offshoreoperations. In some examples, the crane 108 is configured to lift one ormore components of a wind turbine generator (WTG). The jack-up 100 asshown in FIG. 1 is arranged to install WTGs. In other examples, thejack-up 100 is arranged to install or maintain other offshorestructures.

The jack-up 100 as shown in FIG. 1 is positioned adjacent to a(transition piece) TP 118 of a WTG. The TP 118 is ready to receive oneor more WTG components 220 such as the WTG tower 222, the WTG nacelle224, and the WTG blades 226.

The crane 108 comprises a boom 110 which is resting on a boom rest 112.The boom 110 of the crane 108 is positioned on the boom rest 112 whenthe jack-up 100 is sailing between locations. The boom rest 112 ismounted on an accommodation block 114. In examples, there are additionalaccommodation blocks (not show) arranged on a deck 116 of the hull 102.The boom 110 is moveable to an operational position as shown in e.g.FIGS. 2 and 3 in order to hoist loads. The crane 108 and the operationthereof is known and will not be described in further detail.

The hull 102 comprises a deck 116 for storing equipment for the offshoreinstallation operation. In some examples, one or more WTG components 220are stored on the deck 116. For the purposes of clarity, no WTGcomponents 220 have been shown in FIG. 1 .

A problem with existing jack-up rigs which are used to install multipleWTGs in a designated area is that the jack-up rigs must sail back toport to be resupplied. This means that the jack-up rig spends timesailing to port which could be used installing more WTGs. Examplesdescribed in this disclosure provide methods and apparatuses forresupplying the jack-up 100 without requiring the jack-up 100 to sailback to port.

Turning to FIG. 2 , the jack-up 100 will be described in further detail.FIG. 2 shows a side view of the jack-up 100 with an unsecured vessel 206according to an example.

The jack-up 100 as shown in FIG. 2 is in an operational configuration.The moveable legs 104 a, 104 b are extended and feet 208 a, 208 bmounted on the moveable legs 104 a, 104 b are partially embedded in thesoft seafloor 200. This means that the jack-up 100 is stable and able tolift heavy loads with the crane 108.

The vessel 206 comprises a barge 212 tethered to an anchor handlingvessel 214. The anchor handling vessel 214 is arranged to transport thebarge 212 into the vicinity of the jack-up 100. In some examples, thevessel 206 is a barge 212 which comprises propulsors (not shown) formoving the barge 212 under its own power and no anchor handling vessel214 is required. In some examples the anchor handling vessel 214 isinstead another powered vessel such as platform supply vessel (PSV),multipurpose support vessel (MSV) tug boats, ice breaker, patrol boat,coast guard vessel, navy vessel, fire-fighting vessel, or any othersuitable vessel for managing the movement the barge 212. The term“vessel” 206 is a powered barge 212, an unpowered barge 212, or acombination of a barge 212 and another powered vessel 214 such as ananchor handling vessel 214.

The barge 212 comprises a deck 216 for securing and transporting loadsto the jack-up 100. As shown in FIG. 2 , a cargo load 218 is positionedon the deck 216. The cargo load 218 is one or more WTG components 220for installing on the TP 118. Specifically, the WTG components 220comprise one or more towers 222, one or more nacelles 224 and one ormore blades 226. In other examples, the cargo load 218 can beadditionally or alternatively one or more of equipment, personnel,and/or supplies for the jack-up 100. In other examples, the cargo load218 can be additionally or alternatively one or more of a transitionpiece, a monopile, a jacket and/or any other components of an offshorewind turbine generator or wind turbine generator farm.

Optionally, the WTG components 220 are securely mounted to a cargocarrying platform 228 comprises a frame 230 for surrounding the cargoload 218. The cargo carrying platform 228 and the frame 230 will bediscussed in further detail below. FIG. 2 also shows another cargocarrying platform 232 with a similar frame 230 which is empty andpositioned on the deck 116 of the jack-up 100. In some examples, thedeck 116 of the jack-up 100 has clear space for receiving one or morefull or empty load carrying platforms 228,232 on the deck 116 of thejack-up 100. In some examples, the load carrying platforms 228, 232 arereceived on the deck 116 between two of the moveable legs 104 b, 104 c.

In an example (not shown), the WTG components 220 are mounted directlyon the barge deck 216. However, as shown in FIG. 2 , the cargo carryingplatform 228 is secured to the deck 216 of the barge 212 with at leastone securing mechanism (not shown). In some examples, the at least onesecuring mechanism can be a twistlock mechanism or a quick release clampfor selectively securing and releasing the cargo carrying platform 228to the deck 216 of the barge 212. The at least one securing mechanism insome examples can be mounted on the cargo carrying platform 228.

As shown in FIG. 2 , the anchor handling vessel 214 is guiding the barge212 towards the jack-up 100. In FIG. 2 , the barge 212 is not coupled tothe jack-up 100. This means that the barge 212 and the anchor handlingvessel 214 will move relative to the jack-up 100 due to the motion ofthe sea (e.g. heave, sway, surge, roll, pitch and/or yaw of the barge212 and/or the anchor handling vessel 214).

This means that if the weather conditions are too rough, the barge 212and the anchor handling vessel 214 cannot approach the jack-up 100. Oncethere is a suitably calm weather window, the barge 212 and the anchorhandling vessel 214 move towards the jack-up 100.

Turning to FIG. 3 , the method of securing the barge 212 will bedescribed in further detail. FIG. 3 shows a side view of an offshorejack-up 100 with a secured vessel 206 e.g. the barge 212 according to anexample.

At least a portion 300 of the barge 212 is moved underneath the hull 102of the offshore jack-up 100 when the hull 102 is positioned out of thewater 204 and the moveable legs 104 a, 104 b engage the seafloor 200.The jack-up 100 is in the operational configuration and the hull 102 isabove the surface 202 of the water 204. In this way, there is clearancebetween the bottom 302 of the hull 102 and the surface 202 of the water204 for receiving the portion 300 of the barge 212.

The hull 102 of the jack-up 100 may comprise at least one guidestructure 304 for laterally positioning the portion 300 of the barge 212underneath the hull 102 or within a cut-out 400 of the hull 102. Thecut-out 400 is described in further detail below. In some examples,there is a first lateral guide structure 304 a and a second lateralguide structure 304 b for limiting the lateral movement of the barge 212with respect to the hull 102 or with respect to the cut-out 400. Thefirst and second lateral guide structures 304 a, 304 b are best shown inFIG. 5 . In other examples, there is a single guide structure 304mounted on the underside of the hull 102 for guiding the barge 212.

This means that if the barge 212 is moving sideways with respect to thehull 102, for example due to currents, the first and second lateralguide structures 304 a, 304 b will prevent the barge 212 from collidingwith the moveable legs 104 a, 104 b, 104 c, 104 d when the barge 212 isunderneath the hull 102. In addition, the first and second lateral guidestructures 304 a, 304 b limit the movement of the barge 212 with respectto the hull 102 and therefore this prevents the frame 230 and the WTGcomponents 220 from colliding with the jack-up 100. The first and secondlateral guide structures 304 a, 304 b extend downwardly from the hull102 and project towards the surface 202 of the water 204.

In an example, optionally the hull 102 of the jack-up 100 comprises atleast one stop structure 306 for limiting the extent the barge 212 movesforward underneath the hull 102. In another example, there are severalstop structures 306 for limiting the extent the barge 212 moves forwardunderneath the hull 102. In another example, there is not a stopstructure 306 and the anchor handling vessel 214 maintains the positionof the barge 212 with respect to the jack-up 100 before the barge 212 issecured to the jack-up 100. Similarly, in another example, there are nofirst and second lateral guide structures 304 a, 304 b and the anchorhandling vessel 214 maintains the position of the barge 212 with respectto the jack-up 100.

The at least one stop structure 306 extends downwardly from the hull 102and projects towards the surface 202 of the water 204. In some examples,the at least one stop structure 306 and the first and second lateralguide structures 304 a, 304 b comprise an open lattice structure. Thisallows the water 204 to flow through the at least one stop structure 306and the first and second lateral guide structures 304 a, 304 b andreduce the drag on the jack-up 100 when the jack-up 100 is being moved.

As shown in FIG. 3 , the crane 108 has hoisted the empty cargo carryingplatform 232 and lowered the empty cargo carrying platform 232 on to thedeck 216 of the barge 212. This means that the barge 212 can be used tosupply loads 218 and retrieve empty load carrying platform 232.Accordingly, the jack-up 100 can be replenished more efficiently if theload carrying platforms 228, 232 are reused.

The jack-up 100 will now be described in further detail with respect toFIGS. 4 and 5 . FIG. 4 shows a plan view of an offshore jack-up 100according to an example. FIG. 5 shows an underneath plan view of anoffshore jack-up 100 according to an example. For the purposes ofclarity, FIGS. 4 and 5 are shown without the frame 230 or the WTGcomponents 220.

The hull 102 comprises a cut-out 400 at one end of the jack-up 100. Inthis way, a portion of the hull 102 comprises first arm 402 and a secondarm 404 which project out and define the cut-out 400. The cut-out 400 isarranged to receive a portion of the barge 212 or the cargo carryingplatform 228.

This means the hull 102 comprises a cut-out portion 400 whereby the deck216 of the barge 212 is accessible from above when at least a portion300 of the barge 212 is underneath the hull 102 of the offshore jack-up100. This means that the cargo load 218, for example the cargo carryingplatform 228 comprising the WTG components 220 can be lifting verticallyoff the deck 216 of the barge 212. In some examples, the cargo carryingplatform 228 is lifted through the cut-out 400 in the hull 102.

In the example shown in FIGS. 4 and 5 , the cut-out 400 is in theperiphery of the hull 102 of the jack-up 100. In another example (notshown) which is less preferred, the cut-out 400 is located in the centreof the deck 116 of the jack-up 100. This means that the deck 116 of thejack-up 100 comprises a hole for receiving the cargo carrying platform228.

In an example, the crane 108 comprises a working area A extending overthe cut-out 400 of the hull 102. Accordingly, the crane 108 can hoistobjects from the deck 216 of the barge 212 and lower them on to the deck116 of the jack-up 100. The working area A covers most of the deck 116of the jack-up 100 and the location of the TP 118. In other examples,the working area A of the crane 108 covers the entire deck 116 of thejack-up 100. This means that the crane 108 can hoist WTG components 220from the deck 116 of the jack-up 100 and/or the deck 216 of the barge212. The crane 108 can then lower the WTG components 220 onto the deck116 of the jack-up 100 or the TP 118.

FIG. 4 shows the hull 102 comprising a lifting mechanism 406 mounted onhull 102. In an example the lifting mechanism 406 is mounted around theperiphery 408 of the cut-out 400. The lifting mechanism 406 isconfigured to lift the cargo carrying platform 228 between a firstposition on the deck 216 of the barge 212 and a second position whereinthe cargo carrying platform 228 is clear of the deck 216 of the barge212. When the lifting mechanism 406 lifts the cargo carrying platform228 into the second position, the cargo carrying platform 228 is nolonger in physical contact with the barge 212. In this respect, thecargo carrying platform 228 is fixed with respect to the liftingmechanism 406 when in the second position. This means that the movementof the barge 212 due to the water 204 does not move the load carryingplatform 406.

In an example, the lifting mechanism 406 lifts the cargo carryingplatform 228 in a vertical distance D1 (as shown in FIG. 9 ). In someexamples, the distance D1 is 3 m. In some examples, the verticaldistance D1 is 1 m to 5 m. In some examples, the lifting mechanism 406lifts the cargo carrying platform 228 to a height above the deck 216 ofthe barge 212 where the deck 216 of the barge 212 cannot impact theunderside of the cargo carrying platform 228. The vertical distance D1can be varied depending on the weather conditions and the size of thewaves. In some examples, the vertical distance D1 is greater than thevertical displacement of the barge 212 experiences due to the waves e.g.heave. For example, if the barge 212 experiences a heave of plus orminus 2 m, then the lifting mechanism 406 lifts the cargo carryingplatform 228 a vertical distance D1 of greater than 2 m.

Accordingly, as soon as the lifting mechanism 406 lifts the cargocarrying platform 228 off the barge 212, the barge 212 can be moved outfrom underneath the hull 102. This means that there can be a quicktransfer of the cargo load 218 and the WTG components 220 to the jack-up100 from the barge 212. This means that the barge 212 and the anchorhandling vessel 214 can wait near the jack-up 100 and transfer the cargoload 218 to the jack-up 100 in a small calm weather window.

FIG. 4 shows the lifting mechanism 406 is a plurality of lifting arms406. For the purposes of clarity only one lifting arm 406 has beenlabelled in FIG. 4 . In an example, the lifting arms 406 are spacedalong the first arm 402 and the second arm 404. This means that theplurality of lifting arms 406 each lift the cargo carrying platform 228.FIG. 4 shows that there are eight lifting arms 406, however, in otherexamples there can be any other number of suitable lifting arms 406. Inone example, there can be two lifting arms 406 which are positionedeither side of the centre of gravity of the cargo carrying platform 228.In other examples, there can be any other number of lifting arms 406e.g. three, four, six, ten etc.

Turning to FIG. 5 , the underside of the jack-up 100 will now bedescribed. FIG. 5 shows a dotted outline of the barge 212 position withrespect to the jack-up 100.

In an example, a stabilizing mechanism 502, 504, 506, 508, 510, 512 ismounted on the jack-up 100. In an example, the stabilizing mechanism502, 504, 506, 508, 510, 512 comprises a plurality of stabilizingmechanisms 502, 504, 506, 508, 510, 512. In an example, the stabilizingmechanism 502, 504, 506, 508, 510, 512 is a plurality of stabilizingarms 502, 504, 506, 508, 510, 512. In an example, a plurality ofstabilizing arms 502, 504, 506, 508, 510, 512 are mounted on the hull102. The stabilizing arms 502, 504, 506, 508, 510, 512 are engageablewith the barge 212. In an example, the stabilizing arms 502, 504, 506,508, 510, 512 are engageable with the structure of the barge 212 such asthe deck 216 or any other suitable portion of the barge 212. Thestabilizing arms 502, 504, 506, 508, 510, 512 are engageable with thedeck 216 of the barge 212 positioned underneath the hull 102 or withinthe cut-out 400. The stabilizing arms 502, 504, 506, 508, 510, 512 pushdown on the deck 216 of the barge 212 and this reduces the relativemovement of the barge 212 with respect to the jack-up 100. When thestabilizing arms 502, 504, 506, 508, 510, 512 push down on the deck 216of the barge 212, the buoyant force acting on the barge 212 increases.This results in the barge 212 being engaged with the jack-up 100 stopsor limits the relative movement therebetween. In other words, the wavesand current of the water 204 acting on the barge 212 do not cause thebarge 212 to move relative to the jack-up 100 when the stabilizing arms502, 504, 506, 508, 510, 512 engage the deck 216 of the barge 212.

In an example, when the stabilizing arms 502, 504, 506, 508, 510, 512engage with the deck 216, the stabilizing arms 502, 504, 506, 508, 510,512 dampen the movement of the barge 212. The stabilizing arms 502, 504,506, 508, 510, 512 comprise a dampener such as a hydraulic piston 700,704 (described in further detail below). In some examples, the dampener700, 704 is coupled to the stabilizing mechanism and can be one or moreof a spring, a resilient material, or an electro-mechanical dampener,cables and a winch or any other suitable means for dampening themovement of the barge 212.

In an example, the stabilizing mechanism 502 is a single pad (not shown)that engages the deck 216 of the barge 212. The single pad is asubstantially flat planar surface that engages a substantial area of thedeck 216. Since the single pad is of a large area, the pad can push downon the deck 216 of the barge 212 along most of the barge 212. In thisway, the stabilizing mechanism 502 comprises a single engaging elementfor stabilizing the barge 212.

In some examples, the stabilizing arms 502, 504, 506, 508, 510, 512 aremounted on the underside of the hull 102. Each of the stabilizing arms502, 504, 506, 508, 510, 512 are extendible underneath the hull 102towards the surface 202 of the water 204.

In an example, the stabilizing arms 502, 504, 506, 508, 510, 512 arespaced along the hull 102. The stabilizing arms 502, 504, 506, 508, 510,512 are arranged to engage both sides of the barge 212 along thelongitudinal length of the barge 212. As shown in FIG. 5 there are sixstabilizing arms 502, 504, 506, 508, 510, 512. However, in otherexamples, there can be three or more stabilizing arms 502, 504, 506,508, 510, 512. In the less preferred example with only three stabilizingarms, there are a first and second stabilising arm 502, 504 at the sidesof the barge 212. A third stabilizing arm 514 (shown in dotted lines) ispositioned at the bow of the barge 212 aligned with the centreline ofthe barge 212. In other examples, there can be any number of stabilizingarms 502, 504, 506, 508, 510, 512.

In an example, the jack-up 100 comprises a moveable coupling mechanism(not shown) mounted on cut-out 400. The moveable coupling mechanism isconfigured to releasably engage with the bow of the barge 212 when thebarge 212 abuts the stop structure 306. In some examples, the couplingmechanism is mounted to the stop structure 306. In some examples, afirst part of the coupling mechanism is mounted on the stop structure306 and a second part of the coupling mechanism is mounted on the bow ofthe barge 212. In some examples, the first part of the couplingmechanism and the second part of the coupling mechanism are a latch andcatch mechanism. In some examples, the barge 212 is pivotable about themoveable coupling mechanism before the plurality of stabilizing arms502, 504, 506, 508, 510, 512 engage the deck 216 of the barge 212.

In an example, at least one pair of stabilizing arms 502, 504, 506, 508,510, 512 engages the deck 216 on opposites sides of the centre ofbuoyancy B of the barge 212. In an example, there are at least two pairsof stabilizing arms 502, 504, 506, 508, 510, 512 engages the deck 216 onopposites sides of the centre of buoyancy B of the barge 212. In anexample, one stabilizing arm 514 can be part of two pairs 514, 502 and514, 504 of stabilizing arms on opposites sides of the centre ofbuoyancy B of the barge 212. This means that when the stabilizing arms502, 504, 506, 508, 510, 512 push down on the deck 216 of the barge 212,the turning moments about the centre of buoyancy B are balanced.Accordingly, the barge 212 is not subjected to a rolling or a pitchingmotion due to the force of the stabilizing arms 502, 504, 506, 508, 510,512 acting on the deck 216 of the barge 212.

In an example, the plurality of stabilizing arms 502, 504, 506, 508,510, 512 are mounted adjacent to the first lateral guide structure 304 aand the second lateral guide structure 304 b. This means that when thebarge 212 is aligned between the first lateral guide structure 304 a andthe second lateral guide structure 304 b, the stabilizing arms 502, 504,506, 508, 510, 512 are aligned correctly for engaging with the deck 216of the barge 212. In some examples, the stabilizing arms 502, 504, 506,508, 510, 512 are mounted to the first lateral guide structure 304 a andthe second lateral guide structure 304 b. The stabilizing arms 502, 504,506, 508, 510, 512 each comprise an engagement head 516 projectinginwardly towards the barge 212. For the purposes of clarity only oneengagement head 516 has been labelled in FIG. 5 .

As can be seen from FIG. 6 , when the barge 212 is in position, theframe 230 can be lifted off from the deck 216 of the barge 212. FIG. 6shows a plan view of an offshore jack-up 100 with the barge 212 securedto the jack-up 100 according to an example.

FIG. 6 shows the anchor handling vessel 214 pushing the barge 212 intoposition with respect to the jack-up 100. The barge 212 comprises astern cut-out 600 for receiving and engaging with the bow 602 of theanchor handling vessel 214. The stern cut-out 600 engaging with the bow602 provides for a stable connection between the anchor handling vessel214 and the barge 212 when the anchor handling vessel 214 pushes thebarge 212.

The barge 212 has been pushed into position and abuts the stop structure306 (not shown in FIG. 6 ) and is aligned between the first lateralguide structure 304 a and the second lateral guide structure 304 b(again not shown in FIG. 6 ). The frame 230 is ready to be lifted offthe deck 216 of the barge 212 once the barge 212 has been secured withrespect to the jack-up 100.

The WTG components 220 are shown mounted on the frame 230. Inparticular, the blades 226 may extend out sideways beyond the footprintof the hull 102. Of course, the WTG components 220 can be orientated inany direction as required. If the WTG components 220 are oversized e.g.wider than the cut-out 400 width W (as shown in FIG. 4 ), then theoversized WTG components 220 such as the blades 226 are positioned at asuitable height and orientation. For example, the oversized componentse.g. blades 226 are positioned such that the blades 226 do not collidewith the first arm 402 and/or the second arm 404 of the hull 102 whenthe cargo carrying platform 228 is lifted from the first position to thesecond position.

The steps of the securing and transferring method will now be describedin further detail with respect to FIGS. 7 to 9, 10, 12 and 13 . FIGS. 7to 9 show a front side view of an offshore jack-up 100 with the barge212 at different steps of securing the barge 212 and transferring theload 218. For the purposes of clarity, only the barge 212 (and not theanchor handling vessel 214) is shown in FIGS. 7 to 9 .

Turning briefly to FIG. 10 , the cargo carrying platform 228 will bebriefly described. FIG. 10 shows a perspective view of a cargo carryingplatform 228 according to an example. FIG. 10 shows the cargo carryingplatform 228 comprising a frame 230 which surrounds the periphery 1000of the cargo carrying platform 228. The frame 230 surrounds the cargoload 218 and protects the supply load from being damaged during liftingand moving operations. This means that the frame 230 can be handled bythe lifting mechanism 406 and the crane 108. In this way, the frame 230protects the cargo load 218 e.g. WTG components 220 from minor damagesuch as scratches, dents etc. This means that the WTG components 220 areless likely to need painting or repair after installation.

The cargo carrying platform 228 is substantially planar and comprises aplurality of securing mechanisms 604 or lashing points. FIG. 6 showsclamps 604 for clamping to the bottom of the WTG towers 222 to maintainthe WTG towers 222 in an upright position. The securing mechanisms 604can be clamps or other suitable securing mechanisms 604. Furthersecuring mechanisms 604 such as clamps can be used with the WTG nacelle224 and the WTG blades 226. In some examples, the cargo carryingplatform 228 receives WTG components 220 for two WTGs. In otherexamples, each cargo carrying platform 228 is configured to receive theWTG components 220 for a single WTG. In other examples, each cargocarrying platform 228 is configured to receive the WTG components 220for any number of WTGs e.g. three, four etc WTGs.

The frame 230 comprises an elevated fastening position 1002 for securingthe blades 226. The elevated fastening position 1002 is adjacent to thefootprint of the cargo carrying platform 228. This can be seen in FIG. 6when viewing the empty load carrying platform 232. In an example, theframe 230 comprises a plurality of bracing struts for strengthening theframe 230.

The cargo carrying platform 228 comprises a plurality of vertical posts1004. Each of the vertical posts 1004 comprises a lateral projection1006 each engageable with one of the lifting arms 406. In some examples,the lateral projections 1006 are optional. Indeed, the lifting arms 406can lift the cargo carrying platform 228 from underneath the cargocarrying platform 228. Alternatively in other examples, the cargocarrying platform 228 comprises holes for receiving reciprocal pegsmounted on the lifting arms 406.

In some examples, the frame 230 is optional. Indeed, the cargo carryingplatform 228 is only a flat horizontal platform. In other examples, thecargo carrying platform 228 is a securely removeable top deck 216 of thebarge 212.

Turning back to FIGS. 7 to 9 , the method will now be described. Thecargo load 218 e.g. the WTG components 220 are not shown in FIGS. 7 to 9for the purposes of clarity. The supply carrying platform 228 is mountedon the deck 216 of the barge 212.

In FIG. 7 , the barge 212 has been moved such that at least a portion300 of the barge 212 is underneath the hull 102 of the offshore orwithin a cut-out 400 of the hull 102 jack-up 100 as shown in step 1200of FIG. 12 . FIGS. 12 and 13 show a flow diagram of methods according toan example. The barge 212 as shown in FIG. 7 is not in engagement withthe stabilizing arms 502, 504. Furthermore, the lifting arms 406 a onthe port side of the barge 212 and the lifting arms 406 b on thestarboard side of the barge 212 are not in engagement with the lateralprojections 1006 a, 1006 b on the cargo carrying platform 228.

This means that the barge 212 can move relative to the jack-up 100. Theposition of the cargo carrying platform 228 is the same as shown in FIG.6 . That is, the cargo carrying platform 228 is within the cut-out 400of the hull 102.

In an example, the stabilizing arms 502, 504 and the lifting arms 406 a,406 b are actuated with hydraulics. Each of the stabilizing arms 502,504 and the lifting arms 406 a, 406 b are respectively coupled to ahydraulic actuator 700, 704, 702, 706. The hydraulic actuators 700, 702,704, 706 are coupled to a hydraulic system (not shown) for controllingand actuating the hydraulic actuators 700, 702, 704, 706. In an example,each of the stabilizing arms 502, 504 and the lifting arms 406 a, 406 bare coupled to another mechanism for actuating and extending thestabilizing arms 502, 504 and the lifting arms 406 a, 406 b. Forexample, the mechanism can be a rack and pinion mechanism, mechanicallinkage, or any other suitable mechanism for extending and retractingthe stabilizing arms 502, 504 and the lifting arms 406 a, 406 b.

Whilst reference in FIGS. 7 to 9 is made to the stabilizing arms 502,504 and the lifting arms 406 a, 406 b, the same mechanisms and methodsof operation are applicable to the other stabilizing arms 502, 504, 506,508, 510, 512, 514 and the lifting arms 406 discussed in reference tothe previous FIGS. 1 to 6 .

Once the barge 212 is in position, the stabilizing arms 502, 504 areextended to secure the barge 212 as shown in step 1300 in FIG. 13 . Theplurality of stabilizing arms 502, 504 mounted on the hull 102 areextended and engage against the deck 216 of the barge 212 as shown instep 1202 of FIG. 12 . In an example, the stabilizing arms 502, 504 candampen the movement of the barge 212 due to the water 204 and thisallows for a soft engagement with the deck 216 of the barge 212.

As can be seen from FIG. 8 , the hydraulic actuators 700, 704 have beenactuated and extend the stabilizing arms 502, 504 until the engagementheads 516 a, 516 b are in physical engagement with the deck 216 of thebarge 212. Once the engagement heads 516 a, 516 b are seated correctlyon the deck 216, then the hydraulic actuators 700, 704 continue to beactuated and extend the stabilizing arms 502, 504 further. Accordingly,the stabilizing arms 502, 504 are pushed against the deck 216 of thebarge 212 to increase the buoyant force acting on the barge 212 as shownin step 1204 in FIG. 12 . In some examples, the steps 1202 and 1204 canbe one continuous movement. Alternatively, there can be a pause betweensteps 1202 and 1204 in order to check that the engagement heads 516 a,516 b are seated correctly on the deck 216.

In some examples, the plurality of the stabilizing arms 502, 504 engagethe deck 216 at substantially the same time. This means that the barge212 does not experience a turning moment about the centre of buoyancy asthe stabilizing arms push down on the barge 212. In other examples, thestabilizing arms 502, 504 engage the deck 216 at slightly differenttimes in order to accommodate different parts of the barge 212 moving atdifferent rates.

This means that the stabilizing arms 502, 504 push the barge 212 intothe water 204 by a vertical distance D2. This prevents the barge 212from moving with respect to the jack-up 100. This means that the barge212 is secured to the jack-up 100. In some examples, the verticaldistance D2 is between 0.1 to 2 m. In some other examples, the verticaldistance D2 is between 0.3 to 1.5 m. In some other examples, thevertical distance D2 is between 0.5 to 1 m.

In some examples the barge 212 is a monohulled vessel. In some examples,the barge 212 is a multihull vessel as shown in FIGS. 7 to 9 . FIGS. 7to 9 show the barge 212 have two hulls 800, 802, but in other examplesthe barge 212 can comprise any number of hulls. This means that thevolume of water that is displaced when the stabilizing arms 502, 504 arepushed down in step 1204 is reduced. Accordingly, the force required topush the barge 212 down with the stabilizing arms 502, 504 is reducedcompared to pushing down on a monohulled barge 212

After the barge 212 is secured with respect to the jack-up 100, the FIG.9 shows that the hydraulic actuators 702, 706 have been actuated andextend the lifting arms 406 a, 406 b so that they engage the lateralprojections 1006 a, 1006 b of the cargo carrying platform 228. In thisway, the lifting mechanism 406 mounted on the jack-up 100 is engagedwith a cargo carrying platform 228 positioned on the barge 212 as shownin step 1302 in FIG. 13 . Once the lifting arms 406 a, 406 b haveengaged the lateral projections 1006 a, 1006 b, the lifting arms 406 a,406 b lift the cargo carrying platform 228 between a first position onthe barge 212 and a second position clear of the barge 212 as shown instep 1304 of FIG. 13 .

In some examples, the steps 1302 and 1304 can be one continuousmovement. Alternatively, there can be a pause between steps 1302 and1304 in order to check that the lifting arms 406 a, 406 b are engagedcorrectly with the cargo carrying platform 228.

In some examples, the plurality of the lifting arms 406 a, 406 b engagethe lateral projections 1006 a, 1006 b at substantially the same time.This means that the cargo carrying platform 228 is lifted in a stablemanner. In some examples, the lifting arms 406 a, 406 b move atdifferent rates in order ensure that the cargo remains balanced on thecargo carrying platform 228.

As shown in FIG. 9 and previously discussed above, the lifting arms 406a, 406 b lift the cargo carrying platform 228 by a vertical distance D1.Once the cargo carrying platform 228 has disengaged from the barge 212,the cargo carrying platform 228 is fixed with respect to the liftingarms 406 a, 406 b. In other words, the motion of the water 204 will notaffect the cargo carrying platform 228 once it is in the secondposition.

In some examples, once the cargo carrying platform 228 is in the secondposition, the crane 108 hoists the cargo carrying platform 228. Thecrane 108 may hoist the cargo carrying platform 228 to another part ofthe deck 116 of the jack-up 100 as shown in FIG. 6 . The crane 108 mayhoist another cargo carrying platform 232 from the jack-up 100 to thebarge 212 at this point as shown in FIG. 3 .

In some examples, when the barge 212 is secured to the jack-up 100 asdescribed in step 1204, the crane 108 can place a load on the deck 216of the barge 212. The load can be an empty cargo carrying platform 232as described above.

In some examples, the engagement heads 516 on the stabilizing arms 502,504, 506, 508, 510, 512, 514 comprise optional self-seating engagementheads. FIGS. 11 a, 11 b, 11 c shown different example couplings betweenthe stabilizing arms 502, 504, 506, 508, 510, 512, 514 and the deck 216with different shapes of engagement heads 516. FIG. 11 a shows asemi-spherical engagement head 516 or elongated curved head configuredto seat in a reciprocally curved hole 1100 in the deck 216 of the barge212.

FIG. 11 b shows an upstanding peg 1102 mounted on the deck 216configured to seat in a reciprocal hole 1106 in the engagement head 516.

FIG. 11 c shows a conical engagement head 516 configured to seat in areciprocally conically curved hole 1104 in the deck 216 of the barge212. In other examples, the lifting arms 406 and the lateral projections1106 comprise similar couplings to those shown in FIGS. 11 a to 11 c .In other examples, the surfaces on the engagement heads 516 and the deck216 are flat.

Another example will now be described with respect to FIGS. 14 and 15 .FIG. 14 shows an underneath plan view of an offshore jack-up 100according to an example. FIG. 15 shows a plan view of an offshorejack-up 100 with a secured vessel according to an example. FIGS. 14 and15 show examples which are similar to the examples described inreference to FIGS. 1 to 13 . FIG. 14 shows a barge 1400 which is smallerthan the barge 212 described in the previous examples. In particular,the barge 1400 is aligned within the cut-out 400 of the hull 102. Inthis way, the barge 1400 does not have a portion of the barge 1400 whichis underneath the hull 102. Instead, at portion of the barge 1400 iswholly contained within the cut-out 400. Some or all of the length ofthe barge 1400 can be aligned within the cut-out 400. In some examples,the barge 1400 can project out from the cut-out 400 away from thejack-up 100.

The cargo carrying platform 228 as shown in FIG. 14 is lifted from thebarge 212 by the lifting mechanism 406 in the same way as discussedabove with respect to the previous examples.

Similarly, the stabilizing mechanism 1500 operates in the same way atthe stabilizing mechanism 502, 504, 506, 508, 510, 512 as discussed inreference to the previous examples shown in FIGS. 1 to 13 . However, theplacement of the stabilizing arms 1502, 1504, 1506, 1508 has beenadapted to the barge 1400. Since the barge 1400 is smaller, the centreof buoyancy B has moved and the stabilizing arms 1502, 1504, 1506, 1508are moved accordingly. In this way, there maintained four pairs 1) 1502,1506 and 2) 1502, 1504 and 3) 1506, 1508 and 4) 1508, 1504 ofstabilizing arms on opposites sides of the centre of buoyancy B of thebarge 1400.

In another example, the shape, size, orientation, extension, andplacement of the stabilizing mechanisms 502, 504, 506, 508, 510, 512,1502, 1504, 1506, 1508 and the lifting mechanism 406 are configurableand adaptable to different vessels 212. For example, different barges212 can have different shape, sizes and draft depending on the cargo andother factors.

In another embodiment two or more embodiments are combined. Features ofone embodiment can be combined with features of other embodiments.

Embodiments of the present invention have been discussed with particularreference to the examples illustrated. However it will be appreciatedthat variations and modifications may be made to the examples describedwithin the scope of the invention.

The invention claimed is:
 1. A method of supplying a load between avessel and an offshore jack-up, the offshore jack-up having a hull, aplurality of moveable legs engageable with the seafloor, and astabilizing mechanism mounted thereon, the hull having a first guidestructure and a second guide structure, and the plurality of moveablelegs configured to move with respect to the hull to position the hullout of water, the method comprising: positioning a portion of the vesselbetween the first guide structure and the second guide structure tolaterally position the vessel underneath the hull or within a cut-out inthe hull when the hull is positioned out of the water and the pluralityof moveable legs engage the seafloor; pushing the stabilizing mechanismdown on the vessel to increase a buoyant force acting on the vessel, andto limit movement of the vessel with respect to the hull of the offshorejack-up; and lifting a cargo carrying frame between a first position onthe vessel and a second position clear of the vessel with a liftingmechanism mounted on the offshore jack-up.
 2. The method according toclaim 1, wherein the cargo carrying frame surrounds at least a portionof the load.
 3. The method according to claim 1, wherein the cargocarrying frame is mountable to a deck of the vessel.
 4. The methodaccording to claim 3, wherein the cargo carrying frame includes aplurality of sea fastenings configured to releasably secure the cargocarrying frame to the deck of the vessel.
 5. The method according toclaim 1, wherein the lifting comprises: hoisting the cargo carryingframe with a crane.
 6. The method according to claim 1, furthercomprising: positioning the cargo carrying frame within the cut-out inthe hull before the pushing.
 7. The method according to claim 6, whereinthe lifting comprises: lifting the cargo carrying frame through thecut-out in the hull.
 8. The method according to claim 1, furthercomprising: hoisting, by a crane mounted on the offshore jack-up,another cargo carrying frame from the offshore jack-up to the vessel. 9.The method according to claim 1, further comprising: securing the loadto the cargo carrying frame with at least one attachment mechanism. 10.The method according to claim 1, wherein the stabilizing mechanismincludes a plurality of hydraulically actuated arms.
 11. The methodaccording to claim 1, further comprising: extending the stabilizingmechanism underneath the hull.
 12. The method according to claim 1,further comprising: limiting forward movement of the vessel underneaththe hull using at least one third guide structure of the hull.
 13. Themethod according to claim 1, wherein the cargo carrying frame isconfigured to carry one or more of a wind turbine tower, a nacelle, awind turbine blade, or a wind turbine component.
 14. An offshore jack-upcomprising: a hull; a plurality of moveable legs configured to engagewith the seafloor, and to move with respect to the hull to position thehull out of water when the plurality of moveable legs engage theseafloor; a first guide structure and a second guide structure mountedto the hull, the first guide structure and the second guide structureconfigured to laterally position a vessel underneath the hull or withina cut-out in the hull when the hull is positioned out of the water; astabilizing mechanism mounted on the offshore jack-up, the stabilizingmechanism configured to push down on the vessel to increase a buoyantforce acting on the vessel, and to limit movement of the vessel withrespect to the hull of the offshore jack-up; and a lifting mechanismconfigured to lift a cargo carrying frame between a first position onthe vessel and a second position clear of the vessel.
 15. The offshorejack-up according to claim 14, wherein the lifting mechanism is a cranemounted on the offshore jack-up.
 16. The offshore jack-up according toclaim 14, further comprising: at least one attachment mechanismconfigured to secure a load to the cargo carrying frame.
 17. Theoffshore jack-up according to claim 14, wherein the stabilizingmechanism includes a plurality of hydraulically actuated arms.
 18. Theoffshore jack-up according to claim 14, wherein the stabilizingmechanism is configured to extend underneath the hull.
 19. The offshorejack-up according to claim 14, wherein the hull includes at least onethird guide structure configured to limit forward movement of the vesselunderneath the hull.
 20. A method of supplying a load between a vesseland an offshore jack-up, the offshore jack-up having a hull, a pluralityof moveable legs engageable with the seafloor, and a stabilizingmechanism mounted thereon, the hull having a first guide structure and asecond guide structure, and the plurality of moveable legs configured tomove with respect to the hull to position the hull out of water, themethod comprising: positioning a portion of the vessel between the firstguide structure and the second guide structure to laterally position thevessel underneath the hull or within a cut-out in the hull when the hullis positioned out of the water and the plurality of moveable legs engagethe seafloor; pushing the stabilizing mechanism down on the vessel toincrease a buoyant force acting on the vessel, and to limit movement ofthe vessel with respect to the hull of the offshore jack-up; and liftingthe load between a first position on the vessel and a second positionclear of the vessel with a lifting mechanism mounted on the offshorejack-up.
 21. An offshore jack-up comprising: a hull; a plurality ofmoveable legs configured to engage with the seafloor, the plurality ofmoveable legs configured to move with respect to the hull to positionthe hull out of water when the plurality of moveable legs engage theseafloor; a first guide structure and a second guide structure mountedto the hull, the first guide structure and the second guide structureconfigured to laterally position a vessel underneath the hull or withina cut-out in the hull when the hull is positioned out of the water; astabilizing mechanism mounted on the offshore jack-up, the stabilizingmechanism configured to push down on the vessel to increase a buoyantforce acting on the vessel, and to limit movement of the vessel withrespect to the hull of the offshore jack-up; and a lifting mechanismconfigured to lift a load between a first position on the vessel and asecond position clear of the vessel.
 22. The offshore jack-up of claim21, wherein the lifting mechanism is a crane mounted on the offshorejack-up.
 23. The offshore jack-up according to claim 21, wherein thestabilizing mechanism includes a plurality of hydraulically actuatedarms.
 24. The offshore jack-up according to claim 21, wherein thestabilizing mechanism is configured to extend underneath the hull. 25.The offshore jack-up according to claim 21, wherein the hull includes atleast one third guide structure configured to limit forward movement ofthe vessel underneath the hull.